Irregular metal nanocavity for efficient near band-edge light-trapping in organic and inorganic photovoltaic materials

In this work, we demonstrate the absorption of the light with wavelength close to the absorption edge of materials could be largely enhanced by the incorporation of irregular metal nanodots. These nanodots were accomplished by low-cost method with negligible amount of usage. The metal nanodots works as nano-antenna and nano-cavities for light coupling and guiding. At 800 nm, the organic material exhibit approximately 30 % light absorption, which is almost zero without Au nanodots. For the In-organic material, the light absorption increase from ~ 10 % to ~ 50 % at 800 nm with the incorporation of Au nanodots. This enhancement indicate with minimum usage of metal, the light absorption could be largely enhanced, and is useful for high efficiency solar cells.